deciding UFS vs ZFS
Daniel Staal
DStaal at usa.net
Sat Jul 19 20:03:33 UTC 2014
--As of July 18, 2014 6:04:16 PM +0100, RW is alleged to have said:
>> "I was really more interested in whether ZFS (with ARC) is faster than
>> UFS with FreeBSD's own file caching. A lot of people say that putting
>> an OS on SSD gives a significant speed-up. 16GB should be more than
>> enough to keep the important system files in memory, so it sounds like
>> smarter caching might be useful."
>>
>> If you want speed sure UFS is faster on the same machine, but that's
>> because its doing less.
>
> Yes, I know ZFS has overheads, but ARC is potentially better than OS
> caching. The question was whether, with a decent amount memory, ZFS can
> actually be faster than UFS.
--As for the rest, it is mine.
Checking would take extensive work, and I think it would be *heavily*
workload/hardware/tuning dependent, but I suspect there are probably cases
where it would be.
For a similar type of example: Turning on compression in ZFS can improve
speed, depending on the data and the hardware. If it takes less time to
compress/uncompress data than it does to write the difference to disk it
speeds up; so with highly compressible data and light compression you often
get higher speeds.
There are several of that types of trade-offs available in ZFS, and you can
tune for different uses. I don't think anyone has done comparisons, but
it's probably possible that ZFS is faster under certain circumstances, even
with a one-disk pool.
Daniel T. Staal
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